U.S. patent number 6,315,778 [Application Number 09/396,502] was granted by the patent office on 2001-11-13 for apparatus for creating a continuous annular lesion.
This patent grant is currently assigned to C. R. Bard, Inc.. Invention is credited to Gary S. Falwell, Sean Forde, Richard Gambale, Michel Haissaguerre, Donald Patterson.
United States Patent |
6,315,778 |
Gambale , et al. |
November 13, 2001 |
Apparatus for creating a continuous annular lesion
Abstract
A medical device is disclosed which includes a deformable
electrode device. In one illustrative embodiment, the deformable
electrode is in the form of a braided member, at least a portion of
which is electrically conductive. The braided member is extended
over an elongated inner member, such as a guide wire, catheter
shaft, or the like. A proximal sheath is slidably extended over the
inner member and is connected to the braided, electrically
conductive member. The proximal sheath may be advanced distally to
deform the braided member so that it defines a distally facing,
ablative ring, and is operative to form an annular lesion.
Inventors: |
Gambale; Richard (Tyngsboro,
MA), Falwell; Gary S. (Manchester, NH), Patterson;
Donald (North Chelmsford, MA), Haissaguerre; Michel
(Talence, FR), Forde; Sean (Watertown, MA) |
Assignee: |
C. R. Bard, Inc. (Murray Hill,
NJ)
|
Family
ID: |
23567452 |
Appl.
No.: |
09/396,502 |
Filed: |
September 10, 1999 |
Current U.S.
Class: |
606/41; 606/46;
606/47; 607/101; 607/122 |
Current CPC
Class: |
A61B
18/1492 (20130101); A61B 2017/003 (20130101); A61B
2017/22068 (20130101); A61B 2018/00214 (20130101); A61B
2018/00261 (20130101); A61B 2018/00285 (20130101); A61B
2018/00375 (20130101); A61B 2018/00577 (20130101); A61B
2018/00797 (20130101); A61B 2018/00815 (20130101); A61B
2018/00821 (20130101) |
Current International
Class: |
A61B
18/14 (20060101); A61B 17/22 (20060101); A61B
018/18 () |
Field of
Search: |
;606/41,22,25,46,47
;607/101,102,150 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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0771547 A2 |
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Jul 1997 |
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EP |
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2 271932A |
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May 1994 |
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GB |
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WO 96/10961 |
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Apr 1996 |
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WO |
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WO 93/16632 |
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Sep 1993 |
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WO |
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WO 94/21165 |
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Sep 1994 |
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WO |
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WO 94/21168 |
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Sep 1994 |
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WO |
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WO 94/21167 |
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Sep 1994 |
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WO |
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WO 97/17892 |
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May 1997 |
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WO |
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WO 95/01751 |
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Jan 1995 |
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WO |
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WO 95/10318 |
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Apr 1995 |
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WO |
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WO 95/10319 |
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Apr 1995 |
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WO |
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Primary Examiner: Dvorak; Linda C. M.
Assistant Examiner: Ruddy; David
Attorney, Agent or Firm: Darby & Darby
Claims
What is claimed is:
1. A medical device for ablating a ring of tissue, the medical
device comprising:
an inner member;
an electrically conductive member extended over the member, and
including a proximal end and a distal end with a ring of ablative
material defined therebetween, the electrically conductive member
having a collapsed position in which the electrically conductive
member extends in generally collinear fashion with the inner member
and a deployed position in which the ring of ablative material is
spaced radially outwardly from the inner member and is disposed
distal to the distal end of the electrically conductive member;
and
an electrode deployment device slidably extended over the member
and connected to the braided conductive member, the electrode
deployment device being advanceable over the inner member to force
the conductive member to deform and thereby define the distally
facing ring.
2. The medical device of claim 1, further including an expandable
stabilizing and centering structure connected to the inner member
at a location distal to the braided conductive member.
3. The medical device of claim 1, further including a retractable
sheath slidably extendable over the inner member and the
electrically conductive member.
4. The medical device of claim 2, wherein the stabilizing and
centering structure is formed of a mesh.
5. The medical device of claim 2, wherein the stabilizing and
centering structure comprises an expandable balloon.
6. A medical device for ablating a ring of tissue, the medical
device comprising:
an inner member;
a braided, electrically conductive member extended over the inner
member, and including a proximal end and a distal end, the
electrically conductive member being deformable to define a
distally facing ring of ablative material; and
an electrode deployment device slidably extended over the inner
member and connected to the braided conductive member, the
electrode deployment device being advanceable over the inner member
to force the conductive member to deform and thereby define the
distally facing ring,
wherein the braided, electrically conductive member comprises a
filter portion and an electrically conductive portion, with the
filter portion being connected to the electrode deployment
device.
7. The medical device of claim 1, wherein the inner member is
electrically conductive and is connected to the electrically
conductive member to deliver electrical energy thereto.
8. The medical device of claim 1, wherein a selected portion of the
braided, electrically conductive member is masked to be
non-conductive.
9. The medical device of claim 1, further including a temperature
sensing device connected to the electrically conductive member.
10. A medical device for ablating a ring of tissue, the medical
device comprising:
an elongated inner member;
an electrically conductive member extended over the inner member
and including a proximal end and a distal end with a ring of
ablative material defined therebetween, the electrically conductive
member having a collapsed position in which the electrically
conductive member extends in generally collinear fashion with the
inner member and a deployed position in which the ring of ablative
material is spaced radially outwardly from the inner member and is
disposed distal to the distal end of the electrically conductive
member; and
means for deforming the electrically conductive member into the
deployed position.
11. The medical device of claim 10, wherein the means for deforming
comprises a proximal sheath slidably extended over the inner member
and connected to the braided, electrically conductive member, and a
stop disposed distally of the proximal sheath, such that with the
proximal sheath advanced distally, the sheath and stop cooperate to
deform the braided, electrically conductive member.
12. The medical device of claim 10, further including an expandable
stabilizing and centering structure connected to the inner tubular
member at a location distal to the electrically conductive
member.
13. The medical device of claim 10, further including a retractable
sheath slidably extendable over the inner member and the
electrically conductive member.
14. The medical device of claim 10, wherein the stabilizing and
centering structure is formed of a mesh.
15. The medical device of claim 10, wherein the stabilizing and
centering structure comprises an expandable balloon.
16. A medical device for ablating a ring of tissue, the medical
device comprising:
an elongated inner member;
a braided, electrically conductive member extended over the inner
member; and
means for deforming the braided, electrically conductive member to
define a distally facing ring of ablative material,
wherein the braided, electrically conductive member comprises a
filter portion and an electrically conductive portion, with the
filter portion being connected to the proximal sheath.
17. The medical device of claim 10, wherein the inner member is
electrically conductive and is connected to the electrically
conductive member to deliver electrical energy thereto.
18. The medical device of claim 10, wherein a selected portion of
the electrically conductive member is masked to be
non-conductive.
19. The medical device of claim 12, wherein a selected portion of
the electrically conductive member is masked to be
non-conductive.
20. A medical device for ablating a ring of tissue, the medical
device comprising:
an elongated inner member;
an expandable stabilizing and centering member mounted on the inner
member, the centering member being expandable to anchor at least a
portion of the inner member within a passageway; and
means on the inner member for creating a generally annular lesion,
said means comprising an electrically conductive member extended
over the inner member and including a proximal end and a distal end
with a ring of ablative material defined therebetween, the
electrically conductive member having a collapsed position in which
the electrically conductive member extends in generally collinear
fashion with the inner member and a deployed position in which the
ring of ablative material is spaced radially outwardly from the
inner member and is disposed distal to the distal end of the
electrically conductive member.
21. The medical device of claim 20, wherein the means for creating
comprises an expandable, electrically conductive member extended
over the inner member.
22. The medical device of claim 20, wherein the means for creating
comprises an expandable balloon connected to the inner member, the
balloon including an ablative member which assumes a generally
annular, distally facing configuration when the balloon is
inflated.
23. The medical device of claim 21, further including a retractable
sheath slidably extendable over the inner member and the
electrically conductive member.
24. The medical device of claim 20, wherein the stabilizing and
centering member is formed of a mesh.
25. The medical device of claim 20, wherein the stabilizing and
centering structure comprises an expandable balloon.
26. A medical device for ablating a ring of tissue, the medical
device comprising:
an elongated inner member;
an expandable stabilizing and centering member mounted on the inner
member, the centering member being expandable to anchor at least a
portion of the inner member within a passageway; and
an expandable, braided, electrically conductive member extended
over the inner member which is adapted to create a generally
annular lesion,
wherein the braided, electrically conductive member comprises a
filter portion and an electrically conductive portion, with the
filter portion being connected to the proximal sheath.
27. The medical device of claim 21, wherein the inner member is
electrically conductive and is connected to the electrically
conductive member to deliver electrical energy thereto.
28. The medical device of claim 21, wherein a selected portion of
the electrically conductive member is masked to be
non-conductive.
29. The medical device of claim 27, wherein a selected portion of
the electrically conductive member is masked to be
non-conductive.
30. A medical device for ablating a ring of tissue, the medical
device comprising:
an inner member;
a braided, electrically conductive member slidably extended over
the member, the electrically conductive member being deformable to
assume a generally conical configuration and define a distally
facing, ablative ring;
a proximal sheath slidably extended over the member and connected
to a proximal end of the braided, conductive member;
a second sheath slidably extended over the member and connected to
a distal end of the braided, conductive member;
a stop formed on the inner member at a location distal of the
second sheath to prevent movement of the second sheath past the
stop;
wherein the proximal sheath is advanceable distally over the inner
member to force the second sheath against the stop and to cause the
conductive member to deform and assume the generally conical
configuration and define the distally facing ablative ring.
31. The medical device of claim 30, further including an expandable
stabilizing and centering structure connected to the inner member
at a location distal to the braided conductive member.
32. The medical device of claim 30, further including a retractable
sheath slidably extendable over the inner member and the braided,
electrically conductive member.
33. The medical device of claim 31, wherein a distal end of the
centering structure is connected to the inner member, and a
proximal end thereof is connected to the second sheath.
34. The medical device of claim 31, wherein the stabilizing and
centering structure is formed of a mesh.
35. The medical device of claim 31, wherein the stabilizing and
centering structure comprises an expandable balloon.
36. The medical device of claim 30, wherein the braided,
electrically conductive member comprises a filter portion and an
electrically conductive portion, with the filter portion being
connected to the proximal sheath.
37. The medical device of claim 30, wherein the inner member is
electrically conductive and is connected to the braided,
electrically conductive member to deliver electrical energy
thereto.
38. The medical device of claim 30, wherein a selected portion of
the braided, electrically conductive member is masked to be
non-conductive.
39. The medical device of claim 30, wherein a selected portion of
the braided, electrically conductive member is masked to be
non-conductive.
40. The medical device of claim 30, wherein the electrically
conductive member has a collapsed position in which the
electrically conductive member extends in generally collinear
fashion with the inner member and a deployed position in which the
ring of ablative material is spaced radially outwardly from the
inner member and is disposed distal to the distal end of the
electrically conductive member.
Description
FIELD OF THE INVENTION
This invention relates to medical devices for performing ablative
procedures and, more particularly, to a medical device which is
capable of ablating a continuous ring of tissue in a single
step.
BACKGROUND OF THE INVENTION
The human heart is a very complex organ, which relies on both
muscle contraction and electrical impulses to properly function.
The electrical impulses travel through the heart walls, first
through the atria and then the ventricles, causing the
corresponding muscle tissue in the atria and ventricles to
contract. Thus, the atria contract first, followed by the
ventricles. This order is essential for proper functioning of the
heart.
Over time, the electrical impulses traveling through the heart can
begin to travel in improper directions, thereby causing the heart
chambers to contract at improper times. Such a condition is
generally termed a cardiac arrhythmia, and can take many different
forms. When the chambers contract at improper times, the amount of
blood pumped by the heart decreases, which can result in premature
death of the person.
Non-surgical procedures, for example, management with drugs, are
favored in the treatment of cardiac arrhythmias. However, some
arrhythmias are not treatable with drugs. For example, drug therapy
to combat certain types of cardiac arrhythmias has been found to be
successful in only 30 to 50 percent of patients. Because of this
low success rate, another conventional remedy is to perform a
surgical procedure. According to these procedures, various
incisions are made in the heart to block conduction pathways in an
effort to abolish the arrhythmia.
Minimally invasive techniques have been developed which are used to
locate cardiac regions responsible for the cardiac arrhythmia, and
also to disable the short-circuit function of these areas.
According to these techniques, electrical energy is applied to a
portion of the heart tissue to ablate that tissue and produce scars
which interrupt the reentrant conduction pathways. The regions to
be ablated are usually first determined by endocardial mapping
techniques. Mapping typically involves percutaneously introducing a
catheter having one or more electrodes into the patient, passing
the catheter through a blood vessel (e.g. the femoral vein or
aorta) and into an endocardial site (e.g., the atrium or ventricle
of the heart), and inducing a tachycardia so that a continuous,
simultaneous recording can be made with a multichannel recorder at
each of several different endocardial positions. When a tachycardia
focus is located, as indicated in the electrocardiogram recording,
it is marked by means of a fluoroscopic image so that cardiac
arrhythmias at the located site can be ablated. An ablation
catheter with one or more electrodes can then transmit electrical
energy to the tissue adjacent the electrode to create a lesion in
the tissue. One or more suitably positioned lesions will typically
create a region of necrotic tissue which serves to disable the
propagation to the errant impulse caused by the tachycardia
focus.
Ablation is carried out by applying energy to the catheter
electrodes once the electrodes are in contact with the cardiac
tissue. The energy can be, for example, RF, DC, ultrasound,
microwave, or laser radiation. When RF energy is delivered between
the distal tip of a standard electrode catheter and a backplate,
there is a localized RF heating effect. This creates a
well-defined, discrete lesion slightly larger than the tip
electrode (i.e., the "damage range" for the electrode), and also
causes the temperature of the tissue in contact with the electrode
to rise.
It has been found that to overcome focal arrhythmias (a form of
cardiac arrhythmia), it is often necessary to create a continuous,
annular lesion around the ostia (i.e., the openings) of either
veins or arteries leading to or from the atria. Conventional
techniques include applying multiple point sources around the ostia
in an effort to create a continuous lesion. Such a technique is
relatively involved, and requires significant skill and attention
from the clinician performing the procedure.
Accordingly, it will be apparent that there continues to be a need
for a device for performing ablations which facilitates the
creation of continuous, annular lesions. In addition, there exists
the need for such a device which may pass through relatively narrow
passageways to arrive at the site of interest. The instant
invention addresses these and other needs.
SUMMARY OF THE INVENTION
According to one aspect of the invention, a deformable electrode
structure is extended over a tubular inner member, such as a
catheter shaft, guide wire, or the like. The electrode structure is
deformable to assume a distally facing, ablative ring, to
simultaneously ablate a ring of tissue, and is also collapsible to
facilitate manipulation of the device through a patient's
vasculature.
In one illustrative embodiment, the electrode structure is in the
form of an elongated, braided electrode which is slidably extended
over the inner member. An actuating member is also slidably
extended over the inner member and is connected to the braided
electrode. Advancement of the actuating member distally relative to
the inner member causes the braided electrode structure to expand
radially outwardly and assume a generally disk shape. Further
advancement of the actuating member causes the braided electrode
structure to buckle and thereby assume a generally conical shape
which defines the distally facing, ablative ring.
In another illustrative embodiment, the invention includes a
stabilizing and centering member which is configured for insertion
into a patient's vessel (e.g., an artery or vein leading to or from
a chamber of interest) and is expandable inside the lumen to center
the device relative to the lumen, and to anchor the device in place
for reliable deployment of the ablating electrode.
Thus, in one illustrative embodiment, the present invention is
directed to a medical device which includes: an inner tubular
member; a braided, electrically conductive member slidably extended
over the tubular member; first and second sheaths slidably extended
over the tubular member and connected to respective ends of the
braided conductive member; a stop formed on the inner tubular
member at a location distal of the distal-most sheath; wherein the
first sheath is advanceable distally over the inner tubular member
to force the second sheath against the stop and cause the
conductive member to assume a generally conical configuration and
define a distally facing ablative ring.
In another illustrative embodiment, the invention is directed to a
medical device for ablating a ring of tissue, including: an
elongated inner member; a braided, electrically conductive member
slidably extended over the tubular member; and means for deforming
the braided, electrically conductive member to define a ring of
ablative material.
DESCRIPTION OF THE DRAWINGS
Other objects, features and advantages of the invention discussed
in the above summary of the invention will be more clearly
understood from the following detailed description of preferred
embodiments, which are illustrative only, when taken together with
the accompanying drawings in which:
FIG. 1 is a side view of a medical device carrying a deformable
electrode illustrating one embodiment of the present invention;
FIG. 2 is a side view similar to FIG. 1 and showing the medical
device in a deployed position;
FIG. 3 is a side view of another illustrative embodiment of a
medical device according to the invention;
FIG. 4 is a side view similar to FIG. 3 and showing the medical
device in a deployed position;
FIG. 5 is a side view of yet another illustrative embodiment of a
medical device according to the invention; and
FIG. 6 is a side view of still another illustrative embodiment of a
medical device according to the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the drawings, and particularly to FIG. 1, there is
shown a medical device 10 according to one illustrative embodiment
of the present invention. The medical device 10 is operative to
create a continuous, annular lesion around, for example, a
patient's ostium 11 (the opening leading to or from an artery or
vein within an atrium (shown in phantom in FIGS. 1 through 4)). In
one illustrative embodiment, the medical device 10 has a deformable
electrode 12 which is slidably extended over an elongated inner
member 14 and which is displaceable relative to the inner member in
a distal direction along a predetermined travel path, along which
the electrode is transformed from a collapsed position (FIG. 1) to
a deployed position (FIG. 2). An electrode deployment mechanism,
generally designated 16, is provided to selectively transform the
electrode between the respective deployed and collapsed positions.
The medical device may also include a stabilizer and centering
member 28 to securely and reliably position the device 10 relative
to the patient's anatomy.
The inner member 14 may be a solid wire or tube, and preferably is
electrically conductive. The inner member may comprise a guide
wire, catheter shaft, or any other suitable device which is
flexible for manipulation through a patient's vasculature to an
intended site within the patient. In one illustrative embodiment,
the inner member is a steerable catheter which is designed to
facilitate manipulation thereof through the patient's vasculature,
as is well known in the art.
The deformable electrode 12 is preferably in the form of a braided
structure defined by a plurality of interlaced, electrically
conductive filaments 20. In the collapsed position shown in FIG. 1,
the filaments extend in generally collinear fashion with the inner
member 14. The filaments are flexible and capable of being expanded
radially outwardly from the inner member and then deformed into the
distally facing, deployed configuration as shown in FIG. 2, to
define a distally facing, ablative ring 40 that is coaxial with the
inner member 14. The filaments are preferably formed of metallic
elements having relatively small cross-sectional diameters, such
that the filaments can be expanded radially outwardly and then
forced to buckle to assume the inverted, generally conical shape,
without permanent strain to the individual filaments. The filaments
may be round, having a dimension on the order of about 0.002-0.008
inches in diameter. Alternatively, the filaments may be flat,
having a thickness on the order of about 0.001-0.005 inches, and a
width on the order of about 0.002-0.015 inches. By providing a
relatively large number of filaments, the electrode will have
sufficient strength, thereby allowing for the inclusion of smaller,
and therefore more strain-resistant, filaments. In one preferred
embodiment, the filaments are formed of Nitinol.RTM..
Alternatively, the electrode may include nonmetallic elements woven
with metallic elements, with the nonmetallic elements providing
strain resistance to support the metallic elements that provide the
ablative abilities. While the ring 40 is shown in FIGS. 2 and 4 as
having a smooth surface, it will be apparent that the surface may
be ribbed.
Alternatively, the electrode 12 may be formed of one continuous
strand of filament, which is arranged in a helical fashion around
the inner member 14. The filament is expandable between a retracted
position and an extended position to define an ablative ring for
ablating a ring of tissue.
In one illustrative embodiment, the braided electrode 12 has a
significantly greater surface area than a conventional electrode,
and therefore has a relatively low impedance. Typical generators
are designed to work optimally with relatively high electrode
impedance values. Thus, in one embodiment of the invention, a
portion of the electrode is masked so as to be non-conductive,
thereby reducing the conductive surface area of the electrode and
increasing the impedance level of the electrode, for optimal
functioning with conventional generators.
In one embodiment, the medical device 10 includes the electrode
deployment mechanism 16, which includes a proximal sheath 22 that
is slidably extended over the inner member 14. The proximal sheath
is connected to the proximal end of the electrode 12, and may be
slidably advanced over the inner member to displace the electrode
along the inner member. The electrode deployment mechanism further
includes a mid sheath 24 that is slidably extended over the inner
member and connected to the distal end of the electrode 12. Thus,
distal advancement of the proximal sheath causes the electrode as
well as the mid sheath to be driven distally over the inner member
14. A distal stop 26 is preferably mounted on the inner member 14
at a predetermined location, and is configured to engage the distal
end of the mid sheath and prevent further distal displacement of
the mid sheath over the inner member. The distal stop is preferably
in the form of an annular ring that is extended over the inner
member and which has a cross-sectional diameter that is
sufficiently large to engage the distal end of the mid sheath 24
and thereby prevent further advancement of the mid sheath over the
inner member 14.
In one preferred embodiment, the distal end of the mid sheath 24 is
connected to the expandable stabilizing and centering device 28,
which in one illustrative embodiment comprises a mesh of
intertwined filaments 30 which are designed to buckle and flare
radially outwardly when subjected to a compressive load, and which
elongate when tensioned. The stabilizing and centering device is
extended over the inner member 14 at a location distal to the
electrode 12. The distal end 31 of the device 28 is preferably
connected in a secure fashion to the inner member 14 at a
predetermined location thereon. Thus, as the mid sheath 24 is
advanced distally relative to the inner member, the filaments 30
are subjected to compression and buckle to thereby flare radially
outwardly to assume an engaged position (FIG. 2) in which they
engage the inner walls of a patient's lumen 32, such as an artery
or vein leading to or from an atrium. By expanding radially
outwardly in a uniform manner, the device 28 not only serves to
anchor the medical device 10 in place relative to the patient's
lumen, but also serves to center the inner member 14 within the
lumen. In this manner, the electrode 12 will be properly deployed
around the ostia to form a generally annular lesion, as is
described in greater detail below.
Alternatively, the stabilizing and centering device 28 may be in
the form of an expandable balloon 34 (FIGS. 5 and 6) which is in
communication with a source of pressurized fluid (not shown) via a
fluid conduit 36. The balloon is selectively expandable to extend
radially outwardly from the inner member to stabilize the distal
portion of the medical device 10 within the patient's lumen, and to
simultaneously center the inner member 14 relative to the
lumen.
In one illustrative embodiment, the medical device 10 further
includes an elongated, retractable outer sheath 38 which is sized
for slidable extension over the inner member 14, the deformable
electrode 12, and the stabilizing and centering device 28, when the
electrode and centering member are in their respective collapsed
and disengaged positions. The outer sheath serves to protect the
electrode 12 and device 28 during manipulation through the
patient's vasculature. In addition, the outer sheath shields the
electrode from the patient's tissue in the event ablation energy is
prematurely delivered to the electrode.
The respective sheaths 22, 24, and 38 can be advanced and retracted
over the inner member 14 in many different manners, and preferably
are remotely controlled in a control handle (not shown) at the
proximal end of the device 10. One suitable form of handle is
disclosed in U.S. Pat. No. 5,462,527 to Stevens-Wright, the
disclosure of which is hereby expressly incorporated by reference
as if fully set forth herein. As described in the patent, such a
handle includes a slide actuator which is axially displaceable
relative to the handle. The slide actuator is preferably connected
to one of the sheaths, for example, the proximal sheath 22, to
control the movement of the sheath relative to the inner member 14
to drive the electrode member 12 between respective collapsed and
deployed positions, as described above. The handle preferably
includes a second slide actuator or other mechanism coupled to the
retractable outer sheath 38 to selectively retract the sheath in a
proximal direction relative to the inner member 14. Another
suitable form of control handle is disclosed in U.S. Pat. No.
5,611,777 to Bowden et al., which is also expressly incorporated
herein by reference.
As mentioned above, the medical device 10 of the present invention
is also preferably a steerable device, and thus the control handle
also preferably includes a rotatable thumb wheel rotatably mounted
in the handle, which can be rotated by a user to deflect the distal
end of the catheter, as is well known to those skilled in the art,
and as described in greater detail in U.S. Pat. No. 5,462,527,
which has been incorporated herein by reference. As is well known
to those skilled in the art, the thumb wheel (or any other suitable
actuating device) is engaged to one or more pull wires which extend
through the inner member 14 and are connected to the distal end of
the catheter at an off-axis location, whereby tension applied to
one or more of the pull wires causes the distal portion of the
catheter to curve in a predetermined direction or directions.
In one illustrative embodiment, the medical device 10 includes a
temperature sensing device 43, such as a thermocouple, thermistor,
or other suitable device, disposed at a predetermined location on
the braided electrode member 12. The temperature sensing device may
include a plurality of thermocouples which are weaved into the
braided electrode member 12 during formation thereof, or may be one
or more thermocouples or thermistors securely attached to the outer
surface of the electrode member.
In operation, the medical device 10 is advanced through the
patient's vasculature to the intended site of interest, for
example, the ostia 11 of a vein or artery within an atrium, with
the distal end of the inner member 14 extending a predetermined
distance into the vein or artery so that the stabilizing and
centering device 28 is disposed within the vein or artery. The
clinician then retracts the protective sheath 38 to expose the
electrode 12 and the stabilizing and centering device 28. Such
retraction is preferably performed through a control handle as
described above, but may be accomplished in any suitable manner,
including grasping and manually withdrawing the sheath 38. With the
electrode 12 and stabilizing and centering device 28 exposed, the
clinician then manipulates the electrode deployment mechanism 16 to
deploy the electrode 12 and force the device 28 into the engaged
position. In one illustrative embodiment, this is performed by
advancing the proximal sheath 22 in a distal direction, which
forces the electrode 12 and mid sheath 24 to be advanced distally
relative to the inner member 14. With the centering device 28
engaged to the inner member, distal advancement of the mid sheath
causes the device 28 to be compressed so that it expands radially
outwardly and into the engaged position (FIG. 2). In the engaged
position, the device centers the medical device 10 relative to the
patient's lumen.
As the proximal sheath 22 is further advanced over the inner member
14, the mid sheath 24 abuts against the stop 26 and is thereby
prevented from being advanced further along the inner member 14.
Thereafter, continued advancement of the proximal sheath results in
the application of a compressive force to the filaments 20 of the
electrode 12, resulting in the filaments being expanded radially
outwardly from the inner member 14. Continued advancement of the
proximal sheath causes the filaments to buckle and assume a
generally conical, distally facing configuration (FIG. 2). In that
configuration, the electrode defines the distally facing ablative
ring 40 which may be brought into engagement with the patient's
tissue. Ablation energy may then be delivered, for example, through
the conductive inner member 14, to the electrode to ablate a
continuous ring of tissue around the ostium.
While the braided electrode 12 of the device 10 is preferably
manipulated to assume the forwardly facing, conical configuration,
it will be apparent that the electrode may be simply manipulated to
assume a disk shape, with the distally facing surface serving to
ablate the ring of tissue around the ostium or other orifice. In
use, the centering device 28 is situated in place within the
passageway and manipulated into the expanded position. The braided
electrode is then manipulated into a disk shape, with the forwardly
facing surface coming into contact with the tissue around the
ostium. Electrical energy is then delivered to the electrode to
ablate the ring of tissue.
Referring to FIGS. 3 and 4, there is shown another embodiment of
the medical device 10' according to the invention. The device 10'
is identical to the device 10, except for the construction of the
electrode 12'. The electrode 12' is formed in two segments, a
proximal filtering segment 50 and a distal ablation segment 52. The
filtering segment 50 is formed of a plurality of interwoven
filaments, which may or may not be electrically conductive. The
spacing between the filaments in the filtering segment is made
relatively small to collect any particulate matter which flows in
the blood stream during the ablation procedure.
Referring to FIG. 5, there is shown another illustrative embodiment
of a medical device 100 according to the present invention. The
medical device includes a radially expandable member 102 which
includes a first expandable portion defining the stabilizing and
centering member 34, and a second expandable portion defining an
ablative electrode member 106. The expandable member is preferably
an expandable balloon structure, which is selectively expandable by
means of a pressurized fluid delivered through inner lumen 36. The
balloon includes a reinforced central portion 108 which defines the
distal member 34 and the electrode member 106. The electrode member
is constructed such that when it is inflated it assumes a generally
cup-shaped configuration to define a distally facing annulus 110.
The electrode member also includes a flexible, ablative ring
electrode 112 mounted on the annulus, such that when the balloon is
expanded, the ring electrode faces distally and may be brought into
contact with the ostia. Ablative energy is preferably delivered to
the electrode 112 via an electrical lead 114, or any other suitable
manner.
The balloon structure 102 preferably includes through passages
which allow blood to pass from one side thereof to the other. Such
passages may be formed in the balloon structure itself, or
alternatively the inner member 14 may include an internal
passageway (not shown) which allows blood to flow past the balloon
structure 102.
Referring to FIG. 6, there is shown yet another illustrative
embodiment of a medical device 120 according to the invention. The
device includes a braided electrode structure 122, a proximal
sheath 124, and an outer sheath 125, similar to those components
shown in FIG. 1. However, the distal end 127 of the electrode
structure 122 is connected directly to the inner member 126. In
addition, an expandable balloon device 128 is provided adjacent the
distal end of the inner member to serve as the stabilizing and
centering device, and is selectively expanded by pressurized fluid,
as described above in connection with FIG. 5. Thus, the balloon 128
may be expanded to anchor the device 120 in place, and the proximal
sheath 124 may be advanced distally over the inner member to deploy
the electrode structure into the inverted configuration defining
the distally facing ablative ring, as described above.
From the foregoing, it will be apparent to those skilled in the art
that the present invention provides a medical device which is
operative to create continuous, annular lesions. In addition, the
medical device of the present invention provides an easily actuated
mechanism for deploying an electrode to facilitate the creation of
those continuous, annular lesions.
Having thus described preferred embodiments of the present
invention, it is to be understood that the above described
arrangement and system is merely illustrative of the principles of
the present invention, and that other arrangements and systems may
be devised by those skilled in the art without departing from the
spirit and scope of the invention as claimed below.
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